Method of reforming worn rail joint bars



-Nov. 10, 1936. G. LANGFORD 2,060,328

METHOD OF REFORMING WORN RAIL JOINT BARS Fi'led Nov. 18, 1935 fave/2207? GEO/ "p6 Zaggfo-rd MWMvM,

Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE METHOD OF REFORMINGWORN RAIL JOINT BARS My invention pertains to the reforming or reshapingof rail joint bars used to couple rail ends together to form acontinuous track. More particularly it is directed to the reforming ofthe 'worn rail contacting surfaces of a worn rail joint bar. As the wearof a rail joint is greater at its central portion than at its endportions, trouble is encountered in restoring the worn central portion.The end portions interfere because being less worn, they require lessrestoration than does the central portion. But there must be carefulblending of the central and end restorations, for the reason that a wornsurface of a bar must be accurately finished throughout its length. Thegraduation of restoration from' the more worn central portion to theless worn end portions pre sents difficulties, and it is these that myinvention is intended to overcome. My methodof doing this will be fullyunderstood by those skilled in the art, from the following descriptionand accompanying drawing.

In the drawing:

Fig. 1 is an end view of a rail joint bar.

Fig. 2 is an inside view of the bar of Fig. 1 showing the worn conditionof its top fishing or rail bearing surface after use in a joint. I

Fig. 3 is a fragmentary inside view of the top of a bar showing how theworn top fishing surface may be restored.

Fig. 4 is a graphic illustration of the ordinary difficulty encounteredin reforming a worn bar.

Fig. 5 shows a method of reforming used in the prior art.

Figs. 6 and 7 illustrate a variation of means employed in the method ofmy invention.

Fig. 1 is an end view of a bar with top member or head I.

Fig. 2 is an inside view of the bar of Fig. 1 showinghow the bar isusually worn after it has been in service in a joint, fishing surface abin Fig. 1 being worn down to a'-b' in Fig. 2. This wear is greatest atthe central portion 0 of the bar, decreasing through the intermediateportions I, there being in most cases little wear at the end portions E.The top fishing surface is worn'so that it is longitudinally concave atc, this concavity extending into I in amount more or less depending uponthe stiffness of the bar. If the bar is to .be repaired for use again,its top fishing surface worn to a'--b' must be restored by being pushedup to at least its original or normal position ab.

Metal has been worn off the top fishing surface so that in Fig. 1, theinner portion at least of the head of the bar 8 dtc eased in depth,- Forexample, depth 11-0 in Fig. 1 has been decreased at the central portion0 of the bar so that it is less than at the ends E. The bar head having.become thinned centrally in this manner, it then becomes necessary tocompensate for central loss of metal', either by providing more metalcentrally or by pushing it up to its place again as shown in Fig. 3which is an inside view of the bar head of Fig. 2 after the bar isreformed.

In Fig. 3, the worn top fishing surface a'-b is pushed up to its normalposition w-b from the opposing under surface c-d. Broadly described,surface a-b become by wear longitudinally c'on-' cave, is made straightagain by concaving surface c-d. In the prior art, this is disclosed in15 my Patent No. 1,808,467, issued June 2, 1931',

which teaches" movements of metal in a bar by use of longitudinalconvexities in a die. In Fig. 3, surface c-d-is concaved-centrally bya-corresponding die wall longitudinally convexed so as to produce alongitudinal concavity on the bar. For a better understanding of thefollowing description, the word straight used in connection with a baror die; with a surface of a bar or die;

with a die wall; or with a support under a die; will mean longitudinallystraight without any longitudinal convexity. or' concavity. In myinvention I use as a preferred means, two dies, 2. top and a bottom one,both straight. The die walls, corresponding to surfaces of the bar, aremade straight from end to end, each one being machined in by straightcutting from end to end in an ordinary planing or milling machine. Apair of straight dies when closed, defines a die cavity whosecross-section will correspond closely to the cross-section of the bar.The main feature of straight dies is that, when closed empty neither thedie cavity as a whole, nor any one of the three individual cavitiescorresponding, to the 1 three members of a bar, are reduced intransverse or cross-sectional area at center. The cavityas a whole, andits component cavities are uniform' throughout their lengths and notreduced centrally, as would be the case if one or. more die walls wereconvexed longitudinally.

- It is more diflicult to plane or machine die grooves with convexitiesthan it is to make straight grooves without convexities. However in theuse of dies with straight grooves, there is the difliculty of centralwear in the bar to contend with. Fig. 4

is a side view graphically illustrating the ordinary difliculty ofreforming a bar head in straight dies. 4

l representsthe bar head between dies 2 and 3. Under pressure P, die 2is shown closed upon the bar I.

In Fig. 4, the worn fishing surface of a bar is represented by theconcave line a-a'-a which is to be restored to its normal position-11-41. The opposing surface d-dd being unworn must be pushed up todd--d so that the surface a-a'-a may also be pushed up. But inasmuch asthe pressure P has encountered dead resistance at the unworn ends of thebar before any of the pressure reaches the center, this end resistancemust be overcome before any pressure can reach the central portion ofthe bar, made thinner by wear than at the end portions. The pressure Pin Fig. 4 depends entirely upon the resistance of the ends of the bar tothe closing of the dies. In a power press, the top die moves up and downwith a fixed amount of stroke and the greatest pressure occurs when thedies are finally closed upon the bar. If there is no bar in the dies,there will be no pressure when the dies are closed. It is the resistanceof the bar to movement of its metal in the dies that creates pressure Pin the moving die 2, and reactions R in the fixed die 3. It is wellknown in the art what great damage may result when occasionally. twobars may be accidentally placed one on top of the other in the dies.Either the press is stalled and unable to complete its stroke, or elseits main shaft, tierods or some other large part is broken and the presswrecked. In such a case, a 1,000 ton press may be strained far beyondits capacity by the great excess of pressure or dead resistance.

The bar cannot be merely squashed out at its ends so that pressure mayreach the center. Such end resistance is enormous and would soonincapacitate the means for applying pressure. Die 2 will close upon thebar until the pressure P is distributed at the ends as shown by thearrows, but to close further upon the bar and distribute pressure inwardand on the central portion of the bar is impossible unless there be someway of removing or relieving the enormous end resistance, represented bypressure reactions R. Pressure does not necessarily result in materialredistribution of metal as has been described and shown in Fig. 4, wherepressure on the ends of the bar does not result in a redistribution ofmetal there. The bar fills the dies at the ends and resists enormouslythe closing of the dies, as it has no place to go. Longitudinal movementis not appreciable. The pressure is vertical, and the movement of metaltransverse. The important thing is to secure transverse movement ofmetal at the worn center portion of the bar. This cannot be accomplishedas long as the end portions of the bar resist the closing of the dies.End resistance or pressure must be overcome before pressure can reachthe center so as to make the metal flowthere and fill the dies.

Fig. shows how this may be done by using a die-wall convexity v aspreviously referred to and disclosed in my Patent No. 1,808,467, issuedJune 2, 1931. Surface cc'--e-represents the longitudinal convexity of adie-wall used to forcemetal to restore a fishing surface to at least itsnormal position aa-a.' Before pressure P is applied the top surface ofthe bar is concaved longitudinally andits bottom surface is straight.Howeverthe die wall or surface which impinges upon the bottom surface ofthebar is not straight as c--c-c on the bar, but is bulged up orconvexed to cc'-,c. As the top die'2 descends upon the bar I, the firstcontact is at the top ends a, but the first forming pressure is atbottom center as the convex surface c-c'c of die 3 strikes the straightsurface c-c'-c of the bar. T e fi st 11 of material metal is upward atthe center. The vertical amount of convexity in die surface c-c'-c isgreater than the vertical amount of concavity in the worn bar surface,the latter being represented in Fig. 4 by a-a'--a. Die convexity c-c'creduces the central portion of the closed die cavity, and the excess ofdie convexity over bar concavity insures that the closed die cavity willbe too small at center rather than too large as compared with the cavityat the ends. The metal of the bar will then fill the dies at centerbefore it fills the dies at the ends, thereby avoiding dead resistanceat the ends as shown in Fig. 4. As the dies close further, movement ofmetal exten'ds decreasingly toward the ends, and the pressure upon thebar, continually increasing at center extends decreasingly to the ends.When the dies are finally closed, the die cavity is completely filledwith flowed metal at its central portion, dead resistance occurringthere before it reaches the ends. Fig. 5 shows the dies finally closedand the top surface H of the bar reformed. It is the distribution ofpressure when the dies are closed that we are mainly concerned with. Atsuch time, the distribution of pressure would be opposed by a similardistribution of reactions, and pressure P distributed as per the smallarrows on the top surface of the bar pointing downward, would be opposedby a similar distribution of arrows on the bottom surface of the barpointing upward. These increments of the pressure represent incrementsof resistance to further flow of metal. It is not the preliminaryshaping when the metal will bend or flow freely, but the finalresistance when the metal will not fiow freely, that determines how thefinal and greatest pressure should be distributed. The method of Fig. 5has the effect of concentration of pressure P at center as per the smallarrows. End resistance to this pressure is relieved or removed. As die 2closes upon bar I, the effect upon the bar is graduation of pressurefrom the center outward, diminishing toward the ends. End resistance isremoved, and there is nothing to prevent the die 2 from completing itsstroke, and when the stroke is completed, pressure P is concentrated atcenter, diminishing. toward the ends. The effect of this is a wave ofvertical pressure in each direction from the center toward the ends asper the horizontal arrows 4.

Fig. 6, illustrating my invention, is drawn similarly to Figs. 4 and 5.By thinning die 3 sufficiently, it will actually bend under pressure Pwhen die 2 is fully closed, from its normal dotted line position to thefull line position shown. The top die 2 of Fig. 6 is similar in allrespects to the top die 2 in Figs. 4 and 5. However the bottom die 3 isthinned vertically; that is all of its vertical dimensions in amounts sothat the die will not bend under a given pressure, are reduced toamounts which will permit the die to bend under said given pressure.

Die 3 is made of tool steel and normally rests fiat upon a die holder orother suitable support S having its top surface longitudinally straightwithout any vertical convexity, as indicated by the line :vy-z in Fig.6. Support S is of suitable type to permit of lengthwise bending of die3. For this purpose it may be resilient, or may be of relatively softmaterial, or of any other character suitable for the purpose. Theposition of die 3 when first placed upon support S is indicated by thedotted line a:z and the line :cyz in part dotted, the latter coincidingwith the upper surface of support S, initially straight and fiat. Underthe final pressure die 3 is bent or bowed lengthwise, with its centerraised and ends depressed, the support S, at its upper surface beingcorrespondingly bent or shaped, as shown in full lines in Fig. 6.Ordinarily it would seem impossible to bend appreciably a tool steel diethus supported, but under the great reforming pressure commonly used andwith a reduced vertical die thickness related to the pressure, die 3will bend under the pressure as shown. When the pressure is released,the die will spring back to its original position, as will the supportS, if the latter be resilient.

Preferably, the supporting means S for die 3 is relatively soft. Thepractice is to position die 3 upon its supporting means and to then useseveral trial bars to establish the final vertical setting. The settingis as in Fig. 4. The pressure upon the bar is at the end portions only,and the vertically thinned bottom die 3 in Fig. 6 actually bends so thatits top surface assumes the longitudinal convexity c-c'-c conforming tothe worn longitudinal concavity in either the top or bottom surface ofthe bar. In the first few trial bars, most of the pressure is expendedat the ends in crushing and spreading the top surface of the supportingmeans S at the ends so that said supporting means is no longerlongitudinally straight and becomes convexed as shown by the full linesa:"yz". It might be thought that the top surface of the supporting meansS should be so convexed originally, but I find that crushing and forcingit to the desired shape is the simplest and most accurate way, as thetop surface'of the die support becomes shaped to meet actual conditionsand determines the right amount of bending of the die under thepressure. Only a few trial bars are needed to crush the top surface ofthe supporting means at its end portions under a given pressure, but thedie must be thin enough vertically to bend as shown under said givenpressure; and inversely, given a vertical thickness of die, the pressuremust be sufilcient so that the die will bend. End resistance R isrelieved by this bending of the die 3, permitting travel of pressureupon the bar from the center to the ends, so that pressure can reach thecenter of the bar when the die supporting means S has beenlongitudinally convexed on its top surface. Die wall ccc then has aconvexity ccc as in Fig. 5 when the dies are closed upon the bar. Die 3bends down at the ends under pressure P but when the dies are separated,die 3 springs back up at the ends and becomes straight again without thelongitudinal convexity cc'-c being made preferably of tool steel oralloy steel. In this way, the straight die of Fig. 6 made straightoriginally with die wall planed from end to end without convexities aspreviously described may be made to take the shape of the convex-walleddie of Fig. 5, so that the convexity of the die wall will conform to theworn concavity in the bar, thereby reducing the cross-sectional area ofthe die cavity at center to the reduced cross-sectional area of the wornbar at center when the dies are closed upon the bar. From the smallarrows in Fig. 6, it may be seen that the pressure upon the bar firstconcentrated at the ends travels inward as the die 3 bends. The lattermay bend down at the ends or up at the center. In either case, theinitial pressure is confined to the ends of the bar and cannot extendinto the center until the die bends so that the originally straight diesurface ccc will be convexed to ccc. Pressure will then extend to thecentral portion of the bar and cause fiow of metal there until thecentral portion of the die cavity is filled. When the die is finallyfilled at center, the resistance there causes the pressure at center torise rapidly, but this can not take place until after the application ofpressure at the ends and after die 3 bends down at the ends or up at thecenter as described. This is exactly opposite to the effect produced inFig. 5, wherein the first application of pressure begins at the centerand then extends decreasingly outward, the pressure rising rapidly andbeing greatest at center, decreasing to the ends as the dies are finallyclosed upon the bar.

Fig. '7 shows another application of my method. Instead of thinning adie, pressure P may be in- .creased to the point where one of the dieswill bend or where both dies will bend as shown. These dies madeoriginally straight-walled, as previously described become bent andconvexwalled under the pressure and will become straight again when thepressure is removed. In this way I secure the benefits of aconvex-walled die from a. straight-walled die. This is accomplished byso relating the vertical thickness of the die to the pressure, or byrelating the pressure to the vertical thickness of the die that the diewill bend as described, under pressure when the dies are fully closedupon the bar. I may wish-to convex a die -wall of one die and not theother, and this is done by thinning one die and not the other. Thisenables me to avoid any convexity on a selected surface of the baritself.

My method may then be briefly described as one intended to restore aworn or recessed surface of a bar. The preferred means employed is a par of dies which when closed include a cavity conformingto a bar. In thiscavity are one or more die walls made straight longitudinally, said diewall becoming convexed when the dies are closed upon the bar. thisconvexity resulting from a bending down of the die wall under pressureso 'that the die cavity is reduced at center relative to that at theends. A die may be thinned vertically to accomplish this bending, or thepressure may be increased so that its vertical thickness will notprevent its bending and longitudinally convexing, by concentratedpressure, the supporting surface beneath. In either case the die wallmust bend from straightness to convexity, tudinally.

By means of end resistanc I bend the die vertically under pressure sothat its working face comprising one or more die walls is longitudinallyconvex, permitting the reforming pressure to travel inwardly tothecenter. I may not secure such a concentration of pressure at thecenter. as can be attained in the method of Fig. 5, nevertheless thepressure attainedin my method of Fig. 6 may be made enough to properlyreform the worn central portion of the bar after the end portions arereformed. Only moderate pressure is required to make heated metal fill adie cavity, but when the cavity becomes filled, the metal is enormouslyresistant to further forming pressure. The metal being confined in thecavity has no place to go, and further effort to make it go anywherewill result only in enormous and destructive resistance. It is this sortof resistance that is encountered at the end portions of a worn barreformed in longitudinally straight dies. I do notremove this resistancebut I overcome it so that forming pressure may be transmitted inward tothe worn central portion of the bar.

longi- Explained simply, my method is one which employs longitudinallystraight dies, which when closed empty, define a cavity uniform in allof its horizontal and vertical transverse dimensions from end to end.When closed upon a bar, the vertical thickness of one or both dies areso related to a given pressure that said die or dies actually bend asdescribed. When bent, the die cavity becomes smaller at the center thanat the ends, thus adjusting itself to the shape of the bar which becauseof central wear is smaller, that is, of less cross-sectional. area atcenter than at the ends. Dies made originally straight, bend momentarilyunder the pressure, thereby shaping the die cavity momentarily to theshape of the worn bar. Within certain ranges a die will bend a littlemore on a more worn bar than on a less worn bar, and the method thusaccommodates itself to variations of wear.

In its broad aspect my invention is a method of reforming bars wherebythe pressure first reforms the end portions of a bar and then continuesto the center of the bar to reform the center portion. The preferredshaping means is a pair of dies with longitudinally straight walls. Inrespect to the means used, I do not wish to be too strictly limited aslong as I keep within the scope of the method claimed, whereby the firstapplication of pressure is at the ends and then continuing to thecenter. It is possible to use dies wherein there may be a projection orirregularity in a die wall interrupting its straight continuity and yetwhich does not cause a first application of pressure at the center. I,therefore, may use any means other than the preferred means as long as Irestrict myself to reforming pressure, first at the end portions of thebar and then at the center portion.

What I claim is:

1. The method of restoring the fishing surfaces of a worn rail jointbar, which comprises heating the bar to a working temperature andsubjecting it to forming pressure, said forming pressure being firstconcentrated at the end portions of the bar and progressing inrelatively decreasing amount to the center, and finally increasing atcenter so as to efiect a maximum spread of metal at the central portionof the bar.

2. The method of reforming a worn rail joint bar, which comprisesheating the bar to a working temperature and then subjecting it to aforming pressure, said forming pressure, being first concentrated at theend portions of the bar to reform said end portions and progressingtoward the center of the bar to reform intermediate portions of the bar,and finally increasing at the center portion of the bar to reform saidcenter portion.

3. The method of restoring the fishing surfaces of a worn rail jointbar, which comprises heating the bar to a working temperature,subjecting it to forming pressure between opposed dies having barreceiving cavities normally straight lengthwise of the dies, and bendingone of the dies lengthwise by pressure applied first to the end portionsof the bar thereby subjecting the center portion and the end portions ofthe bar to forming pressure by the die surfaces in the closing of thedies and accurately forming the fishing surfaces at said portions of thebar.

4. The method of reforming the centrally worn fishing surface of' a railjoint bar, which comprises heating the bar to a working temperature andsubjecting it to forming pressure, said forming pressure being firstapplied at the end portions of the bar and then extendingto the centerso as to effect a maximum displacement of metal at center to restoresaid centrally worn fishing surface.

5. The method of reforming a worn rail joint bar, which comprisesheating the bar to a working temperature and subjecting it to formingpressure, said forming pressure being first applied at the end portionsof the bar and then at the center portion so as to effect a maximumdisplacement of metal at center to restore one at least of the top andbottom fishing surfaces at the center portion of the bar.

6. The method of reforming a worn rail joint bar, which comprisesheating the bar to a working temperature and subjecting it to formingpressure, said forming pressure being first applied to the end portionsof the bar to reform one at least of the top and bottom fishing surfacesat the end portions, and then being applied to the center portion toreform one at least of the top and bottom fishing surfaces at the centerportion.

GEORGE LANGFORD.

